Concrete materials can be applied by methods of mixing a batch of moldable concrete material, transporting the material (conveyor belts, buckets, hoppers, pumps, and the like), and then spreading such material into forms for setting into a hardened state. Typically, such concrete materials are worked in the forms before the material hardening reaction sets the material in place and becomes no longer pliable. Because the length of time in the hardening can represent dead time in which further work cannot progress until hardening occurs, additives may be added to the concrete material which will accelerate the rate of hardening. However, such additives cannot be so effective that hardening occurs in the application equipment or before completion of the working process to ensure homogeneity in the formed hardened structure. Accordingly, the use of accelerants cannot include accelerants which work too rapidly.
Concrete materials can be applied by either casting or projecting the refractory into place by dry application processes and wet application processes, such as by the “gunnite” and the “shotcrete” processes respectively, to provide a rapid formless application of a refractory. Field performance of gunnited or shotcreted refractory products can be good, but field installations are often affected by the problems of the existing technology which have very limited control of the smoothness and of the thickness of the application. To overcome these problems and achieve both the desired smooth finish and the controlled thickness, the refractory product applied by casting requires custom forms and may have issues with setting or curing times. Often, such setting processes require segmental casting and hardening such that seams are present in the refractory monolith, that is, the finished product is not a true monolithic form but has discontinuities which can be sources of performance problems.
What is needed is a concrete material, method and apparatus of application of such material to enable the continuous forming of a true monolithic structure with controlled dimensions. An objective of the present invention is a concrete material with a controlled hardening rate which can be used to form a continuous monolithic structure having controlled dimensions. Another objective of the present invention is to provide an apparatus capable of applying such material in order to form a seamless monolith without disruption of the surface of the structure and in a manner which can take advantage of the controlled hardening of the material. A further objective of the present invention is a method of using such material and such apparatus, separately or together. These and other objectives are provided herein.